Polyurethane (PU) hardener systems are essential components in two-component (2K) PU coatings. They react with polyol resins to form tough, flexible, and chemically resistant films. These systems are widely used in industrial, automotive, architectural, and marine applications due to their ability to cure at ambient temperatures and deliver high-performance finishes.

Key Characteristics

• Isocyanate-based chemistry (typically HDI, IPDI, MDI)

• Crosslinking capability for enhanced mechanical and chemical resistance

• Available in solvent-based, water-based, and solvent-free formats

• Fast curing at room temperature or accelerated with heat

• Customizable pot life and reactivity depending on formulation needs

• Compatible with a wide range of polyols (polyester, acrylic, polyether)

Functional Benefits

• Excellent adhesion to metal, wood, plastic, and concrete

• High abrasion, UV, and chemical resistance

• Flexible yet tough films that resist cracking and peeling

• Long-term color and gloss retention

• Suitable for low-VOC and eco-friendly formulations

• Enables high solids and low-temperature curing systems

Application Segments

Popular Technologies & Variants

• Aliphatic Isocyanates (HDI, IPDI): UV-stable, ideal for topcoats

• Aromatic Isocyanates (MDI, TDI): High reactivity, used in primers and basecoats

• Blocked Isocyanates: Latent curing systems for heat-activated applications

• Waterborne PU Hardeners: Dispersible isocyanates for low-VOC coatings

• Solvent-free Systems: Used in flooring and sealants for environmental compliance

Polyurethane hardener systems are the reactive engines behind high-performance coatings. Their versatility, durability, and adaptability make them indispensable across industries. Whether you’re formulating for aesthetics, protection, or sustainability, choosing the right PU hardener unlocks the full potential of your coating system.